Taliban fighters have captured a district in the northern part of Afghanistan, according to officials in the country.

The Taliban took over Yamgan district in Badakhshan province on Wednesday after heavy clashes broke out between security forces and the fighters.

"The district fell into the hands of the Taliban fighters late yesterday, but we are fighting the insurgents. Reinforcements are arriving by air as well to take hold of the district," Navid Frotan, the spokesperson for the province's governor, told Al Jazeera.

"The residents of the district are fleeing in fear of the ongoing war. However, the situation will soon be under control."

Zabihullah Mujahid, the Taliban spokesperson, told Al Jazeera that they had completely taken over the district.

"We took over several military vehicles and weapons, and are ready to fight the security forces," he said. "We have raised our flags in the district. Our enemies are defeated again."

A resident of the district told Al Jazeera that the Taliban chanted their slogans after they took over. "They were going around with their flags raised and almost all of them were armed," he said. "We want peace. We have had enough of this cat and mouse game."

Taliban offensive

According to officials, this is the second time the Taliban have taken over the district in the past six months. Badakhshan has become one of the unstable provinces in the north as the Taliban has been gaining a foothold across the country.

In late September, the armed group briefly took over the northern city of Kunduz before it was driven out from the strategic city by Afghan forces backed by US air strikes.

It was the first time the Taliban had made such gains in Kunduz since the US-led invasion ousted them from power in 2001.

Since then, the troops have been fighting the Taliban in 13 provinces, according to Tolo News, an Afghan news channel.

Earlier this month, a breakaway faction of the Taliban elected its own leader, Mullah Mohammed Rasool, prompting speculation over the unity of the group and its future decisions. This was followed by violent clashes between two rival Taliban groups in southern Afghanistan, which resulted in the death of several fighters from both sides.

Merkel sends more soldiers

Meanwhile, Germany, the third biggest supplier of international troops to Afghanistan, announced on Wednesday that it would extend the deployment's mandate until the end of 2016 and slightly boost the size of its contingent.

Chancellor Angela Merkel's cabinet agreed to allow up to 980 soldiers to serve in the NATO mission, up from 850 previously.

Last month, US President Barack Obama announced that the US would extend its military role in the country and keep the current force of 9,800 troops through most of 2016, amid a surge in Taliban attacks.

Under the new plan, the number of US troops would fall to 5,500, starting in 2017.